Nonaccumulating pressure control unit for brake systems



A. MAJNERI 2,516,229 NONACCUMULATING PRESSURE CONTROL UNIT FOR BRAKE SYSTEMS Filed Sept. 9, 194a s Sheets-Sheet 1 July 25, 1950 POSITION 2 POSITION l .|4 v as [2| JNVENTOR.

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IE1|E=E July 25, 1950 L. A. MAJNERI NONACCUMULATING PRESSURE CONTROL UNIT FOR BRAKE SYSTEMS Filed Sept. 9, 1946 lOl 5 Sheets-Sheet 2 INVENTOR.

July 25, 1950 MAJNERI 2,516,229

NONACCUMULATING PRESSURE CONTROL UNIT FOR BRAKE SYSTEMS 3 Sheets-Sheet 3 Filed Sept. 9, 1946 AREA A:

k N VEN TOR. A 00 me 6 Mad/v52 Patented July 25, 1950 INQNAQCUMULATING messune ooNr o ff UNIT yon BRAKE. sys'rnMs- APhliatiQi .Ser em r 9, 1946, eri l. No. was.

This invention relates to hydraulic brake systems of the type frequently used on aircraft equipped with dual'controls enabling the brakes to be independently ope-rated by the pilot and co-pilot of the aircraft. I

One type ofbrakesystem suitable-for installation on aircraft equipped with dual controls; comprises pressure producing control devices in the form of master cylinders serially arranged' between a reservoir for hydraulic fluid mediumand each brake actuator or power brake valve, depending upon the size of the aircraft. More par ticularly such braking systems usually embody one set of master cylinders for each'br-ake. The intake port of one mastercylinder-in each set is connected to the reservoir and the discharge port is connected to the intake port of the other mastercylinder in the same set so that pressure resulting from-manual application of the first master cylinders is transmitted to the second master cylinders. The latter master cylinders are each provided with deliveryports respectively connected directly-to the brakes or indirectly to the brakes through suitable power brake valves.

It follows fromthe above that if for any reason the pilot and co -pilot should; simultaneously apply an operating force orr thei-rrespectivecontrol devicesor master cylinders the'pressure supplied to the brakes will be subs tantially the sum of the forces applied to the control devices or, in other-words, m'ay'range from double to four times the norm'alop'rating pressure seen high brake applying pressures may cause locking of the wheels during landing of the aircraft or may resultin failure of the brakesi' With the above-in view, it is-bhe orthe-objects of this invention to overcome-the above objection by providing an arrangement wherein the maximum pressures obtainable in the braking system does not appreciably exceed specified normal operating pressures regardless-of whether the controldevices ineach set are inadvertently operated simultaneously by the pilot and co-pilot. In other words, eventhoughithecontrbldevices of each set-are serially arranged between the reservoi'r and brake actuator, the combined action of these units; is not accumulative insofar as the pressure at the brake actuator is concernedi Another object or this invention isto-provide' a hydraulic brake system of the above general type, wherein the' actual brake pressure is determined by the control deyices'ubiecte'd to the greatest manual operating-force in instances where both devices of a set are operatedjsiinultaneously.

Still-another object of'tliis invention is to pro-' 4 Claims. (C1. Gil-P5495) taneou'sly or independent vide-an arrangement wherein one control-device of-each set resists manual' operation; in, instances where a iforce is" applied simultaneously to the other co'ntrdldvice-oi the same setand the resistance serves as a warning to the operator of thesaid one controldevice that the other control device is' in operation:

The foregoing aswell-as other objects will be more fully understood as'this description procoed-s; especially when consideredfiin connection with the accompanying drawings whereingfi Figure 1 is a diagram of a= hydraulie'brake system embodying the features of this invention;

Figure 2 is' a longitudinal; sectional view through one"- of the-control devices shown in Figure 3 is an enlarged sectional view showing one set'of control'devices -in' operative relationship? v Figure 4' is a;cross-sectiona l view taken on the line k" l"of"Figure*2-;

Figure 5- is asectionalViewshowinga'modiiied; form of 'c'o1'1'trol 'dev-icef j In Figure 1} of the drawings,"a: hydraulic brake systemis shown} comprising twosets of menu ally v operable control devices" respectively serving" a' pair of brakesfi'iiand 'l 'l." The controlflevices" in one set arein theform of' master-cylinders? and are indicated generally by the numerals l2 and i3. I'Ih'e' control devices in' theother- 'set are also in' the; formof" master cylinders andare designated in the drawings by the reference characters'" [4' and'dfii F the purpose of thisdescrip-j tion; it} will be assumed" hec jntrol devi'cesf first position fbrmam ual pperati n from'thj ots station and"tha t; the control devices I S andlj5aregro1iped in a secondposition in manual operation by the control devices in the first and second "positions are respectively connected to" the usual; manually operable control el'ements" (not shewmso that hecoritr'ol' devices 'eith'erf set ma be 'si inu-lco-pilot. It "Will" further be assumed that the,

Referringja gain to Figure lflof the lfraw ngs.

it will be noted, that iti receiving ends oif'th'e control devices hr the near-gee to a f reservo'i omen ar n connected tof the re'ce v "g ends ofj the control units in the firstfposition. Thedischarge ends, of thgcontrglde es iirfthe firS P'QSit'ib I spe tiv'el'y conneetedito bak actuators H l fl forthefbral es an f 'In'fhe event'the brake system embodies a -power circuit mending co'nd position are on for 'hydr 'U id ends -'are' respecti'vely"v a high pressure accumulator I9 and a reservoir I9, power valves and 2 I of any accepted design may be introduced between the control devices in the first position and the respective brake actuators I1 and I8. In any case the control devices in each set are serially connected between the reservoir I5 and brake actuators so that thebrakes maybe selectively or simultaneously operated from either of the two operating positions described.

As previously stated, the present invention is particularly concerned with avoiding excessive pressure at the brake actuators in the event the master cylinders or control devices atboth positions are operated simultaneously. Briefly, this is accomplished by specially constructing the master cylinders I2 and I4 at the first position so that these master cylinders will by-pass fluid under pressure to the brake actuators as long as the force applied to the master cylinders I3 and IB-atthe second position exceeds any applying f'orce that may be simultaneously applied to the master cylinders I2 and I4. In the event, however,;an applying force is exertedon the master cylinders I2 and I4 which exceeds the applying force on the master cylinders I3 and I5, the former master cylinders will render the latter inoperative insofar as effecting the pressure at the actuators is concerned and will control brake application independently of any applying force exerted on the master cylinders I3 and I5. Actually the construction of the master cylinders I2Yan'd I4 is such that the higher of the brake applying forces exerted simultaneously at both positions determines the pressure at the brake actuators. I With' the above in view, reference is now made {herein detail to the specific construction of the master cylinders I2 and I4. Both of these master cylinders are identical in construction and, accordingly, a description of one will sufilce for the both. Upon reference to Figures 2 and 3, it will be noted that the numeral 22 indicates a cylinder closed at the bottom by a plug 23 and closed ,at the top by a similar plug 24. The two plugs are secured in place by fastener elements 25 1 and an O-ringseal 26 is provided on the plug 2.3 to prevent the escape of fluid in the cylindervpast the plug. 1

A cup-shaped piston 21 is slidably supported in the cylinder 22 and a valve member 28 extends through anopening .or passage 21. in the base, of thepiston. A ring 23 of"resilient material having concentric annular lips 30 is secured to the bottom of the piston with the inner lip engaging the valve member and with the outer lip engaging the inner wall of the cylinder. The construction is such as to prevent leakage of fluid past the piston and valve member. The lower end portion of the valve .memberis bored to form an axial passage 3I having radially outwardly extending ports 32 positioned to connect the upper end of the passage 31 with the interior. of the piston 21. is closed by a cap 33 having an annular enlargement 34 at the upper end and secured to the valve member 28 by a transverse pin 35.

An annular valve seat 35 is formed on the valve member 28 above the ports 32. and is adapted to seat on the bottom wall of the piston around the passage 21' therethrough to prevent the flow of fluid within the cup-shaped piston 21- through the ports 32 and into the passage 3|. The valve member 28 is normally urged in a direction to close the-passage 21' through the piston bya The lower end of the passage 3|:

4 relatively weak coil spring 31 surrounding the valve member and having the lower end engaging the enlargement 34 on the cap 33. The upper end of the coil spring 31 abuts an annular shoulder formed on a sleeve 38 by an enlargement 39. The upper or free end of the enlargement 39 engages the resilient ring 29 between the lips 30 and portions thereof are cut away to provide passages 48 through which fluid admitted to the annular space 4| formed by the enlargement 38 valve member 28 below the ports 32.

annular groove intermediate the ends thereof for receiving an O-ring 45. The O-ring 45 frictionally engages the inner wall of the, piston and prevents the escape offluid in thechamber 44 past the enlargement 43. Fluid is admitted into the chamber 44 throughan axial passage 46 formed in the valve member 28 in alignment with the passage 3I and connected to the chamber 44 by radially extending ports 48, I A manually operable plunger 48 is removably secured to the upper end of the valve member 28 and is formed with an intake port 58 for supplying hydraulic fluid. medium to the passage 46.' v

A coil spring 5| substantially stronger than the coil spring 31 is housed in the cylinder 22 below the piston with the upper end abutting the shoulder or enlargement 34 on the cap 33 with the lower end seated on the plug-.23. Thus, the coil spring 5I normally maintains the upper end of the piston 21 and enlargement 43 on the valve member 28 in abutting engagement with the plug 24. As shown in Figure 2 of the drawings, when the parts are in the abov position, thepassage 21' through the piston is open enabling hydraulic fluid medium to be by-passed through the piston 21 from the passage 46. i

Fluid under pressure is-introduced into the passage 46 through the intakeport 58 and the latter has a fluid,connection;with one of the master cylinders I; or I5.- A As; shown. in Figure '1' 0f the drawings, the intake port 5|) of the master cylinder I2 is connected to-the discharge port 52 of the master cylinder I3, by a;conduit 53 to form one set of serially connected control devices between the reservoir I8 and brake ,actuator I1. The other master cylinder I4 has the intake port 50 connected tothe discharge port 52 of themaster cylinder I5 by a conduit 54 to provide a set of serially connected control devices betweenthe reservoir -I 6 and the brake actuatorIB.

The master cylinders I3 and: I5 at the second position are identical in constructionand may be the same as the master-cylinders I2 and I4 at the first position, if desired. l-loweven in the interests of economy, it ispreferred-to employ master cylinders of orthodox construction at the second. position. One type of, conventionaltypeinderhaving an intake port 56 spaced above the discharge port 52 and connected to the fluid :res

ervoir I'B by a conduit ;51. The bottom of the cylinder is closed by a plug (not shown) andthe pe end .Q ih qyl nd r s cl hva p g 58 and an annular groove 6| is formed inithe outerl urf c f he plug 58 inregistration with; the intake port 56 to-receive fluid from. the. latter.

The annular groove is connectedto. the passae i Gaby a plurality of passages 62' extending-ra-- dially from the passagetll to the annular groove.

6|. An O-ling 63 is retained in a groove formedin the outer surface of the plug 58 beyond the. port 56 and engages the inner wall of. the Y1. incler to revent the escape oin-uid past the plu 58. A second O-ring 64 is retained inv a groove formed in the inner surface ofthe plug 58 ;beyond the upper end of thepassage at and fric tionally engages the-plunger 59 to prevent. the escape of fluid from the passage 69. aslongthe plunger 59.

A cup-shaped piston 65. is slidably supported in the cylinder 55 between the plug 58 and discharge port 52. The base of the piston has a central assage 6t therethrough for slidably receiving a valve member 6.! forming an extension of the plunger 59. An enlargement 68 is formed on the valve member and occupies a position above the base of the cup-shaped piston 65.. The enlargement 63 is formed with a conical surface engageable with a valve seat 69 surrounding the passage 6,6 through the piston 65 ancl'normally urged into engagement-with the seat 69 by a coil Spring 10 surrounding, the valve member 6'! above the enlargement. The bottom of the co l spring '10 rests on the enlargement B8, and the upper end engages an apertured plate ll,- The plate is seated on an annular shoulder 12 formed on the valve member 61 and is held in place by a sprin clip .13. The clip 13 is secured in the upper end of the piston 65- against an. annular flange it extending inwardly from the top ofthe piston.

A cap 15 is secured on the lower end oi the valve member 5'! below the piston 65 and isformed with an annular enlargement 16 atthe upper end providing an annular shoulder H. The, top edge of the enlargement 16 engages a resilient washer is fixed to the base of the piston .65 and having concentric lips 79. Theouter lip frictionally en gages the inner wall of the cylinder 55 and the inner lip frictionally engages the valve member, Thus, fluid leakage past the piston andyalve member is avoided. A coil spring 39 of greater strength than the spring Ill acts on the shoulder- TI to urge the piston 65 in its uppermost position against the plug 58. r,

In the open position ofthe. valve member '51.; fluid isby-passed thr ugh the valve meinloeimbj a assage 8! iormed'in the lower end of the-valve, member and connected to the p ssage :65 throu the piston 65 by a port 8-2. The passagelll is also connected to the space .83 formed by the annular enlargement 116 on the cap 15 by a port 84. The top edge of the annular enlargement it s cut away to enable fluid to flow from the space .53

to the discharge port 52 in the cylinder 55; 1]

Operation Assuming that it is desired to applyboth brakes It and H from position two; the operator at this position merely depresses the plungers 5.9 of both master cylinders 13 and 15. In so doing the valve members 51 are moved relative to the pistons 65 to closethe passagesfi fi therethrough and the istons 65 are moveddownwardl-y tod sv place fluid in the cylinders-5:.5below the pistons 65 through the dischareeports 1-52, It nul and 14 to the brake. power valves 20 and .2! tov This pressure P1 exerts understood. that the entire system is 1111651 wi h:

fluid so that the fluid in the conduits 5.3 is. dislaced-through the ports 50' in the master oylin ders l2 and it. Since the passa es 21' through the pistons 21 in both the master cylinders 12 and 14 are open, it follows that fluid is Icy-passed through the pistons 21 to the portions of the cylinders 22 below the pistons 21 where it flows through the delivery ports 85 to the power valves- Zll and 2!. The power valves are operated in the usual manner to admit fluid under pressu e from the accumulator 19 to the brake actuators H and I8. It will, of course, be understood that the master cylinders 13 and I5 may be selectively operated in cases where it is desired to appl only one of the brakes.

When the operator at the second position r e-' leases both mas er cylinders 13 and 15, the

springs return the pistons 65 to their up-pert most positions against the stop or plug 58 and in so doing also moves the valve members 5] us Wardly to open the passa es 66 th ough the piss tons 55. As a result, fluid irom the reservoir It may flow through the pistons 65 to replenish the supply in the system.

Amsuming now th t is d sired to pply bo h brakes from the first position, the operator at this position merely depresses the plungers 29' of both master cylinders 12 and I4. Initial downward movement of the plungers 45-9 closes the passages 21' through the pistons '21 and continued downward movement thereof efi'ects: a

corresponding movement of the pistons ill to displace fluid through the delivery ports '85 to the power valves 2-!) and 21. The power valvesare operated in the usual manner by the fluid under pressure to connect the brake actuatorsto the accumulator Hi. When the operator releases the plungers 4.9, the pistons 2? are re turned by the springs 51 to their uppermost po sitions against the stop or plug 26. Inasmuchas the return springs 5! are stronger than the valvesprings fil it follows that the valve members 23 are also moved upwardly to open the passages- 21' through the pistons 21. Since the passages 65 u h he pistons 65 of the master cylinderstheir released positions, and applyi torce F1 is exerted on the actuatin plun ers .59 of the master cylinders I 3 and I5, a line pressure is created that may be expressed by the equation P1=F1/A1 Whfile P; is the and A1 is the pistonared.

it is pointed .out that in the interests of slip plicity he for e required to compress the return equa i n s well spring isignolied in the above as in the following computations, The line pres sure i p sses through the mast r cylinders 12 operate the brakes. upward .force n the piston actuating plunger 49V or the master cylinders e expressed by he equation L2=Pi Aa Inthis equati n, l is the line pressur A2 is he area of the enlargemen expose t the line pres u e.

P1, a d L2 is the force appl e against the area} A2 of the enlargement. The pressure P1 .alsoexerts an upward force on the pistons 2'! of the master cylinders 12 and M which may be expressed as,M ;E (A1Ae)- wherein A; is the;

line or brak pressure In this connection 12 and M, which m y area of the piston andMZ is'the force applied against this area by the line pressure P1. From the above equations it can be seen that the sum oft-the forces (L2+Ma) =P1/A1 and, therefore, equals the force F1. These upwardly acting forces will, of course, oppose any attempt to apply the master cylinders I2 and I4 by the operator so that the latter is warned that the master cylinders I3 and I5 are operative. I

Assuming now that the force F1 applied to the master cylinders at positions two is held constant and that a gradually increasing force F2 is applied to theactuating plungers 49 of the cylinders I2 and I4, it will be noted that the plungers' 49 will not start their downward travel as long as the force F2 is less than the force L2. When the applying force F2 exceeds the force L2 but remains less than the force (L2M2,) the valve members 28 will close the passages 21' through the pistons 21. The pistons 21 remain in their inoperative or uppermost positions, however, until the applying force F2 exceeds the applying force F1. It will be noted from the above that as long as the applying force F2 is lower than the applying force F1, the pressure supplied to the brake remains P1 p. s. i. or, in other words, remains under the control of the master cylinders I3 and I5. During such a condition the force F2 merely acts to relieve the thrusts L2 and M2 from being exerted against the plugs 24.

As the applying force F2 becomes greater than the applying force F1 the pistons 21 move downwardly in their respective cylinders 22 and a line pressure P2 is obtained which exceeds the line pressure P1. The applying pressure P1 is confined in the chambers 44 between the enlargements 43 on the valve members 28 and the base portions of the pistons 21. Thus, the applying pressure P1 tends to force the plungers 49 upwardly and the pistons '21 downwardly with a force equivalent to (A2A3) P1 wherein A3 is the area of the opening 21' in each piston. This latter force tends to open the passages 21 through the pistons 21. However, it will be noted from Figure 3 of the drawings that the force tending to close the passages 21' through the pistons 21 by the valve members 28 is equal to P2 (A1-As). With the applying force F2 greater than the "applying force F1, the line pressure P2 is larger than the pressure P1 and, due to the construction of the control devices, (A1A3) is larger than (A2A3). It is evident, therefore, that the valve remains closed and that the seating forceSz transmitted through the valve seat is Since the pressure P1 is confined to the chambers 44, the pressure P2 supplied to the brakes is P2=F2/A1, which is the same as if the pressure P1 were not applied. It follows from the foregoing that if both sets of master cylinders are simul-,

8 Sinceit-re'duires this increase by area ratio of force F1 to overcome-the force F2 it is advisable to locate the master cylinders I2 and I4 at the pilots stationto make it more diflicult for the co-pilot to-over-ride the pilot.

"The: embodiment of theinvention shown in Figure5 of the'drawings differs from the construction shown in Figure 2 of the drawings in that displacement iseffected by pulling the actuating plunger 90 instead of pushing the latter. The plunger 90 is secured to the upper end of the valve'member 9I and is formed with an intake port 92 which communicates with the upper end of'a passage 93 in the valve member.

An inverted cup-shaped piston 94 is slidably supported in the cylinder 95 and normally engages aplug 96 forming a closure for the bottom of the cylinder. The base of the piston is centrally apertured to provide a passage 9! for freely receiving the valve member BI and the latter is formed with ahead 98 at the lower end. The head 98 is slidably supported in the piston and cooperateswith the base of the latter to provide a chamber 09 which communicates with the passage 93 through ports l90. The chamber 99 is adapted to communicate with the cylinder above the piston through ports. IOI which extend from the passage 91 intermediate the ends thereof and are adapted to be closed by a portion I02 on the valve member when the latter is moved to its uppermost position relative to the piston. The portion I02 is urged into engagement with the base of the piston to close the ports IOI by a coil spring I03 surrounding the valve member and'located in a retainer I04 fixed to the valve member above the piston 94. The upper end of the spring I03 engages the base of the retainer and the lower end of the spring projects through the open end oftheretainer into abutting engagement with-the base'of the piston.

The'piston 94 is yieldably urged into engagement with the plug 90 by a relatively stronger coil spring I05 surrounding the valve member 9I above the retainer I04. The upper end of the spring I05 engages a plate I06 centrally apertured to slidably receive the valve member and adapted to-abut the plug I01 at the top of the cylinder. The lower end of the spring I 05 engages a shoulder formed on a sleeve I00 which is slidably mounted on the valve member in a position to engage a spring washer I09. The washer I09 is fixed to the valve member and acts as a stop for both the retainer I04 and sleeve I08.

The above construction is such that initial upward movement of the plunger 90 moves the valve member 9I relative to the piston 94 sufficiently to close the passage 91 or ports WI and continued movement of the'plunger effects a corresponding upward movement of the piston to displace fiuid fromthe'cylinder above the piston through the delivery port IIO. With theexception of the fact that the operating plunger is pulled insteadof pushed, the unit operates in the same manner as the unit featured in Figure 2 of the drawings. I I

What I claim as my invention is:

1. A fluid pressure operated brake system comprising a brake actuator, a first manually operable pressure producing device of the displacement type having a discharge port, a second manually operable pressure producing device com-prising a cylinder having spaced intake and delivery ports respectively connected to the discharge port of the "first device and to the brake before it could over-ride the effect-0f force F2. '16 actuator, a piston slidable in the cylinder between the ports therein and having a passage therethrough; a valve member supported for sliding movement relative to the piston and having a portion adapted to close the passage through the piston, manually operable means for moving the valve member in a direction to suecessively close the passage and move the piston in a direction toward the delivery port in the cylinder, an enlargement movable with the valve member between intake port and piston and cooperating with the latter to form a chamber communicating with the intake port to receive fluid from the first device, the surface of the enlargement and the surface of the piston subjected to the pressure of the fluid supplied to the chamber by the first device having corresponding areas, and a slidable seal at the enlargement preventing the escape of fluid from the chamber past the enlargement.

2. A fluid pressure operated brake system comprising a brake actuator, a first manually operable pressure producing device of the displacement type having a discharge port, a second manually operable pressure producing device comprising cylinder having spaced intake and delivery ports respectively connected to the discharge port of the first device and to the brake actuator, a piston slidable in the cylinder between the ports therein and having a passage therethrough; a valve member supported for sliding movement relative to the piston and having a portion adapted to close the passage through the piston, manually operable means for moving the valve member in a direction to successively close the passage and move the piston in a direction toward the delivery port in the cylinder, an enlargement movable with the valve member between intake port and piston and cooperating with the latter to form a chamber communicating with the intake port to receive fluid from the first device, the surface of the enlargement and the surface of the piston subjected to the pressure of the fluid supplied to the chamber by the first device having corresponding areas, a slidable seal at the enlargement preventing the es-- cape of fluid from the chamber past the enlargement, spring means normally urging the valve mmber to its open position, a stop engageable with the enlargement to limit opening movement of the valve member by the spring, the area of the enlargement forming one wall of the chamber and the area of the portion of the piston forming the opposite wall of the chamber being substantially the same whereby the pressure supplied to said chamber by the first device is neutralized in the closed position of the valve member.

3. A fluid pressure operated brake system comprising a brake actuator, a first manually operable pressure producing device of the displacement type having a discharge port, a second 10 manually operable pressure producing device comprising a cylinder having a stop at one end and having a delivery port adjacent the opposite end connected to the brake actuator, a piston slidably supported in the cylinder between the stop and delivery port, a valve member controlling a passage through the piston, an enlargement on the valve member normally held against the stop and cooperating with the adjacent side of the piston to form a chamber, a slidable seal at the enlargement preventing the escape of fluid from the chamber past the enlargement, a fluid connection between said chamber and the first pressure producing device, and manually operable means for successively moving the valve member to close the passage through the piston' and to move the piston in a direction to displace fluid through the delivery port to said actuator.

4. A fluid pressure operated brake system comprising a brake actuator, a first manually operable pressure producing device of the displacement type having a discharge port, a second manually operable pressure producing device comprising a cylinder having a stop at one end and having a delivery port adjacent the opposite end connected to the brake actuator, a recessed iston slidably supported in the cylinder between the stop and delivery port with the recess opening toward the stop, a passage through the piston, a valve member controlling a passage through the piston and having limited movement relative to said piston, an enlargement on the valve member slidable in the piston recess and cooperating with the base of the recess to form a chamber, a seal on the enlargement slidably engaging the side wall of the recess to prevent leakage of fluid past the enlargement, a fluid connection between the chamber and discharge port of the first pressure producing device, and manually operable means connected to the valve member for moving the valve member relative to the piston to close the passage through the piston and for subsequently moving the piston to displace fluid in the cylinder through the delivery passage to the brake actuator.

LUDWIG A. MAJNERI.

' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

